You can call it an upset if you’d like, but not judging by the posters plastered all over the No. 7 trains and subway stations promoting the U.S. Open.

Sloane Stephens, the 19-year-old product of Coral Springs, Fla., lived up to the hype as she continued her seed slaying Tuesday. The bubbly Stephens delighted a Louis Armstrong Stadium crowd with a 6-3, 6-4 victory over former French Open champion and No. 22 seed Francesca Schiavone of Italy.

“I just think it’s so cool,’’ Stephens said of the ad campaign. “There’s a blow‑up picture of me. I’m like, ‘Wow, that is awesome.’ Everyone else who walks by, I’m sure they’re like, ‘That’s awesome. That’s cool.’ I love myself. So seeing myself is like unbelievable.’’

Stephens, whose father is deceased Patriots running back John Stephens, doesn’t lack for confidence. When asked if she is the sport’s next superstar, Stephens deadpanned, “She is.’’

Was her victory an upset? “I wouldn’t say that,” Stephens said. “But I think it was time. When they told me I played Schiavone, it’s time. It’s either go big or go home.’’

Stephens, who considers Serena Williams her mentor, burst on the Open scene last year with a run to the third round that included an upset over tough Israeli Shahar Peer. She reached the fourth round of the 2012 French Open and the third round at Wimbledon.

“Wow, 2012 has been pretty good to me,’’ Stephens said.

She also relentlessly regales the media with her tales and phrases and has become Serena’s close friend.

“We’re really good friends,’’ Stephens said. “We really enjoy each other. We just have a really good relationship. Whenever we see each other, we’re laughing and we’re giggling. I feel like I knew her in my past life or something. It’s so strange.’’

Stephens had two match points at 3-5 and the stadium thought it was over when a forehand appeared to hit the baseline, but was called out. She lost the game, then fell behind love-30 on her serve at 4-5. Stephens kept her composure and roared back for the win. She ended the 95-minute first-rounder with a screaming forehand down the line on the dead run.

“I just had to stay within myself,’’ said Stephens, ranked a career-best 44th. “You only get one chance to serve for the match and the crowd carried me.”

The match got testy at 4-4 in the final set and Raonic facing a break point. Giraldo bashed a cross-court backhand service winner — or so it appeared. The shot was called out after Raonic pointed his finger wide, a breach of tennis etiquette. Giraldo exploded, screaming at the umpire. There is no video replay on Court 11.

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Christina McHale, the second-highest seeded U.S. woman at No. 21 behind Williams, lost Tuesday night out on the grandstand to Kiki Bertens, 6-4, 4-6, 6-3.

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Juan Martin del Potro lost his first-round opponent Wednesday as fellow Argentinian David Nalbandian pulled out with a pulled chest muscle. He will be replaced by a to-be-announced lucky loser.